Multiple stage sorption and desorption process and apparatus

Abstract

A process and apparatus for multi-stage sorption and desorption of process gas using a multiple concentric tube apparatus having a thermal supply gas pass through the central conduit creating a thermal wave passing through a high temperature sorption/desorption salt in the innermost annular compartment desorbing prior sorbed process gas followed by passing the thermal wave to an outer annular compartment which together with heat of sorption of process gas in an inner annular compartment desorbs process gas in the outer annular compartment. The process is useful in heat pumps and gas evaporative cooling cycles.

I claim: 
     
       1. A process for multi-stage sorption and desorption comprising: passing process gas in contact with a low temperature salt sorbing said gas at a lower temperature than a high temperature salt in thermal conduction relation thereto and rejecting the heat of sorption;   passing hot thermal supply gas in gas isolated and conductive thermal exchange relation with said high temperature salt having prior sorbed process gas creating a thermal supply heat wave passing through said high temperature salt from a hot thermal supply gas exchange side to an opposite side in gas isolated thermal conduction relation and thermal exchange with said low temperature salt, thereby desorbing process gas from said high temperature salt;   removing desorbed process gas from said high temperature salt;   ceasing passage of said hot thermal supply gas when said thermal supply heat wave reaches said high temperature salt opposite side;   passing said thermal supply heat wave from said high temperature salt opposite side through said low temperature salt having prior sorbed process gas;   passing process gas in contact with said high temperature salt sorbing said process gas at a higher temperature than said low temperature salt and passing the heat of sorption by said high temperature salt to and through said low temperature salt having prior sorbed process gas, heat from said thermal supply wave and from said heat of sorption by said high temperature salt desorbing process gas from said low temperature salt;   removing desorbed process gas from said low temperature salt; and   repeating the above cycle.   
     
     
       2. A process for multi-stage sorption and desorption according to claim 1 wherein the temperature differential for sorption/desorption by said high temperature salt and said low temperature salt is at least 10° C. 
     
     
       3. A process for multi-stage sorption and desorption according to claim wherein said hot thermal supply gas is provided by a gas flame. 
     
     
       4. A process for multi-stage sorption and desorption according to claim 1 wherein said passing hot thermal supply gas and said rejecting the heat of sorption from said low temperature salt is effected by activating a single blower during at least a portion of the time period of said desorbing process gas from said high temperature salt. 
     
     
       5. A process for multi-stage sorption and desorption according to claim 1 wherein thermal transfer between said high temperature salt and said low temperature salt is reduced during at least a portion of the time period of said desorbing process gas from said high temperature salt. 
     
     
       6. A process for multi-stage sorption and desorption according to claim 1 wherein said passing hot thermal supply gas, said rejecting the heat of sorption from said low temperature salt, and thermal transfer between said high temperature salt and said low temperature salt is reduced by activating a single blower during at least a portion of the time period of said desorbing process gas from said high temperature salt. 
     
     
       7. In a process for gas evaporative cooling wherein a refrigerant gas is passed through a condenser condensing said refrigerant gas to liquid refrigerant which is passed to an evaporator boiling the liquid refrigerant by thermal exchange with ambient air thereby producing cooling of said ambient air and refrigerant gas recycled driven by thermal energy through sorption and desorption of the said refrigerant gas, the improvement of utilization of at least a portion of the heat of refrigerant gas sorption for refrigerant gas desorption in a multi-thermal staged process comprising; passing refrigerant gas from said evaporator in contact with a low temperature salt sorbing said refrigerant gas vapor and rejecting the heat of sorption;   passing hot thermal supply gas in gas isolated and conductive thermal exchange relation with said high temperature salt having prior sorbed refrigerant creating a thermal supply heat wave passing through said high temperature salt from a hot thermal supply gas side to an opposite side in gas isolated thermal conductive relation and thermal exchange with said low temperature salt, thereby desorbing refrigerant from said high temperature salt;   removing desorbed refrigerant from said high temperature salt and passing it to said condenser;   ceasing passage of said hot thermal supply gas when said thermal supply heat wave reaches said opposite side of said high temperature salt;   passing said thermal supply heat wave from said high temperature salt opposite side through said low temperature salt having prior sorbed refrigerant;   passing refrigerant gas from said evaporator in contact with said high temperature salt sorbing said refrigerant gas at a higher temperature than said low temperature salt and passing the heat of sorption by said high temperature salt to and through said low temperature salt having prior sorbed refrigerant gas, heat from said thermal supply wave and from said heat of sorption by said high temperature salt desorbing refrigerant from said low temperature salt;   passing desorbed refrigerant gas from said low temperature salt to said condenser; and   repeating the above cycle.   
     
     
       8. In a process for gas evaporative cooling according to claim 7 wherein said refrigerant is ammonia. 
     
     
       9. In a process for gas evaporative cooling according to claim 7 wherein the temperature differential for sorption/desorption by said high temperature salt and said low temperature salt is at least 10° C. 
     
     
       10. In a process for gas evaporative cooling according to claim 7 wherein said hot thermal supply gas is provided by a gas flame. 
     
     
       11. In a process for gas evaporative cooling according to claim 7 wherein said passing hot thermal supply gas and said rejecting the heat of sorption from said low temperature salt is effected by activating a single blower during at least a portion of the time period of said desorbing refrigerant gas from said high temperature salt. 
     
     
       12. In a process for gas evaporative cooling according to claim 7 wherein thermal transfer between said high temperature salt and said low temperature salt is reduced during at least a portion of the time period of said desorbing refrigerant gas from said high temperature salt. 
     
     
       13. An apparatus for multi-stage sorption and desorption comprising: a reactor vessel having a plurality of annular concentric compartments surrounding a gas-tight central passage, the separator between the innermost of said annular concentric compartments and said central passage capable of conductive thermal exchange, the separator between each said compartments being gas-tight and capable of conductive thermal exchange, the outermost wall of the outermost of said annular concentric compartments having a thermal exchange means associated therewith;   means for supplying hot thermal supply gas through said central passage;   means for supplying and removing process gas in desired sequence to and from each of said annular concentric compartments; and   each of said annular compartments containing a salt capable of sorbing and desorbing said process gas at a different temperature arranged in a gradient of said sorbing and desorbing temperatures in adjacent compartments from said innermost to said outermost compartment, the salt capable of said sorbing and desorbing at the highest temperature in said innermost of said annular concentric compartments and the salt capable of said sorbing and desorbing at the lowest temperature in said outermost of said annular concentric compartments.   
     
     
       14. An apparatus for multi-stage sorption and desorption according to claim 13 having two said annular compartments. 
     
     
       15. An apparatus for multi-stage sorption and desorption according to claim 13 wherein at least one of said separators has an expanded heat transfer surface on at least one side thereof. 
     
     
       16. An apparatus for multi-stage sorption and desorption according to claim 13 wherein said means for supplying hot thermal supply gas comprises a gas burner. 
     
     
       17. An apparatus for multi-stage sorption and desorption according to claim 13 having spaced walls between at least two said annular concentric compartments, said spaced walls having axially extending thermally conductive fins therebetween forming passageways for passing cooling gas therethrough. 
     
     
       18. An apparatus for multi-stage sorption and desorption according to claim 13 having an outer reactor wall open at the bottom surrounding said apparatus. 
     
     
       19. An apparatus for multi-stage sorption and desorption according to claim 18 having blower means in an upper portion of said outer reactor wall, said blower means capable of drawing said hot thermal supply gas through said central passage and drawing cooling gas over said thermal exchange means on said outermost wall. 
     
     
       20. An apparatus for multi-stage sorption and desorption according to claim 13 wherein the salts in adjacent compartments provide said gradient of said sorbing and desorbing temperatures in said adjacent compartments to be at least 109° C.